The present invention relates generally to still cameras and particularly to the automated film advance and shutter release used in conjunction with a motor driving a still camera.
Prior art camera drive systems operate in basically two modes--taking single pictures in which the camera operator actuates the shutter mechanism and in the automatic mode in which a sequence of pictures is taken while the shutter mechanism is held in the operative position. In order to permit the operator actuation of the shutter release mechanism, a typical prior art system will stop the drive motor's operation. However, when this device is operated with the shutter release mechanism held down by the camera operator (so that it takes a sequence of still pictures) the motor alternately starts and stops slowing overall frequency of operation.
Additionally the prior art mechanisms for connecting the drive motor to the still camera are relatively complex and difficult to manufacture such that they operate in a reliably consistent manner. Additionally, most prior art couplings require that the drive motor operate a predetermined period of time in order to drive the film advance drum the distance of one frame. Thus the number of rotations of the film advance drum for one camera may be different from the number of rotations for another camera and thus the automatic drive device would not be compatable between the two cameras.
In still other prior art camera drive systems, the camera is set and the film advance drum advanced by one motor and the shutter release is actuated by a different motor. In prior art cameras, it is desirable to ensure that the film advance drive motor has stopped completely prior to releasing the camera shutter in order to provide that the film does not move during the actual exposure. This also reduces the frequency of operation of the camera in the automatic mode.